Digital cameras are commonly incorporated into a wide variety of devices. In this disclosure, a digital camera device refers to any device that can capture one or more digital images, including devices that can capture still images and devices that can capture sequences of images to record video. By way of example, digital camera devices may comprise stand-alone digital cameras or digital video camcorders, camera-equipped wireless communication device handsets such mobile, cellular or satellite radio telephones, camera-equipped personal digital assistants (PDAs), computer devices that include cameras such as so-called “web-cams,” or any devices with imaging or video capabilities.
In digital camera applications, the viewfinder mode refers to a mode in which the digital camera device displays the current view of a camera sensor to the user. The user can examine the viewfinder to determine whether to record a snapshot or record a video sequence. When the user begins recording with the digital camera device, the viewfinder mode may change to an image capture mode (e.g., for snapshots) or a video capture mode (e.g., for video recording). In some digital camera devices, such as stand alone cameras, the viewfinder mode is the default mode of the device. In many digital camera devices, such as mobile phones or PDAs equipped with digital cameras, a camera setting may need to be selected by the user from a plurality of possible operational settings, and the viewfinder mode may comprise a default mode in the camera setting. In some cases, the viewfinder mode can be active while other applications are also active on the device. For example, some mobile phones equipped with digital cameras may be able to handle telephone calls, network searching, internet activity, global positioning system (GPS) functionality, or other applications while in the viewfinder mode. In this case, the user may be able to set the device to a camera setting while talking on the phone, and examine the viewfinder and take snapshots or record video while talking on the phone.
Digital camera devices are often designed to include a bus, which facilitates data transfer between the different modules or units of the device. In computerized architecture, a bus refers to a data transfer subsystem that transfers data or power between computer components. The bus is typically controlled by a bus controller, which may comprise device driver software that executes on a processor of the device. In digital camera applications, the camera sensor may transfer data to the viewfinder over the bus for real-time presentation to the user. At the same time, one or more other units of the device may also use the same bus to transfer other data.